Pre-crush die assembly and method

ABSTRACT

A pre-crush die assembly is utilized for controlled deforming of at least a portion of one or more tubular members to be used in a subsequent hydroforming operation. The tubular member has a centerline extending therethrough. The die assembly comprises at least two dies that move interdependently towards each other to deform the tubular member on opposite sides thereof equally about the centerline of the tubular member where the tubular member is being pre-crushed.

BACKGROUND OF THE INVENTION

The present invention relates to a pre-crush die assembly for controlled deformation of a tubular member, such as, for example, a pipe or conduit having a circular or non-circular cross-section, to be used in a subsequent hydroforming operation.

Hydroforming is the known process of shaping usually a hollow tubular metallic member within a closed mold by subjecting the hollow metallic member to high internal fluid pressure. The high internal fluid pressure permanently deforms the metallic member against the mold surfaces of the closed mold. Hydroforming is used on a large scale for manufacture of frame components for road vehicles and finds application in other manufacturing and industrial processes where a tubular product is formed to very precise dimensions.

One problem associated with hydroforming is known as pinching. Pinching occurs when the outside walls of the tubular member are scraped and deformed during insertion of the tubular member into the dies. Pinching mostly occurs where the die cavity configuration will not accept, without forced engagement, a tubular member that is bent to a considerable degree and/or has a cross-sectional dimension considerably larger than that of the die cavity. This pinching may result in the walls of the tubular member weakening and being subject to rupturing during the hydroforming process.

Accordingly, there is a need to provide a pre-crush tool that partially deforms the tubular member prior to insertion of the tubular member into the die cavity to prevent scraping and weakening of the wall of the tubular member.

BRIEF DESCRIPTION OF THE INVENTION

In the present invention, a pre-crush die assembly is utilized for controlled deforming of at least a portion of a tubular member to be used in a subsequent hydroforming operation. The tubular member has a centerline extending therethrough. The pre-crush die assembly comprises at least two dies that move interdependently towards each other to deform the tubular member on opposite sides thereof equally about the centerline of the tubular member where the tubular member is being pre-crushed. The dies only act against that portion of the tubular member to be pre-crushed and the dies do not act against those portions of the tubular member not to be pre-crushed.

By interdependent movement it is meant that the dies are constructed to move in unison towards and away from each other in opposing directions of equal distance.

In one embodiment of the invention, a pre-crush die assembly is utilized for controlling deforming of at least a portion of a tubular member to be used in a subsequent hydroforming operation. The tubular member has a centerline extending therethrough and the pre-crush die assembly comprises a support table and a sub-assembly. The support table supports the tubular member relative therewith. The sub-assembly is mounted to the support table for movement relative thereto. The sub-assembly comprises a first die and a second die both adapted to move relative to the support table and interdependently of each other between an open position and a closing position deforming the portion of the tubular member. In the open position, the first and second dies are positioned in spaced non-contacting relation to opposing sides of the tubular member. The first and second dies move interdependently in opposing directions towards each other into the closing position to continuously maintain the first and second dies equidistant from the centerline of the tubular member adjacent the portion of the tubular member being deformed.

It is envisaged that if the first and second dies are free to float relative to the support table the first and second dies can self-align equidistant from the tubular member as the two dies engage the tubular member. Alternatively, the first and second dies are positioned in the open position equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed.

The term support table as used herein means any structure that is capable of supporting the dies for relative movement with respect to one another and the support table.

In an embodiment the first and second dies are the only dies utilized in the pre-crush assembly. Alternatively the first and second dies may form one die pair or one die of a set of dies used in the pre-crush assembly.

In another aspect there is provided a method of controlled deformation of at least a portion of a tubular member to be used in a subsequent hydroforming operation by first and second dies, the method comprises the steps of:

positioning the tubular member between the first and second dies in spaced non-contacting relation therewith; and

interdependently moving the first and second dies towards each other to engage and deform the tubular member while continuously maintaining the first and second dies equidistant from the centerline of the tubular member adjacent the portion of the tubular member being deformed.

In one embodiment, the sub-assembly further comprises a first carriage for supporting the first die and a second carriage for supporting the second die. The support table comprises a guide trackway along which the first and second carriages move.

In another embodiment, the first and second carriages each comprises at least one elongate rail having an elongate groove extending along its length and the guide trackway comprises guide members mounted to the support table each having an edge surface portion extending into and along the elongate groove of the elongate rail.

In one embodiment, the sub-assembly comprises a first set of rails adapted to slide relative to the support table, a second set of rails interspaced with the first set of rails and adapted to slide relative to the support table in directions opposite to those of the first rails. The first die is mounted to the first set of rails, and the second die is mounted to the second set of rails.

In another embodiment, the sub-assembly further comprises a first mounting plate connected for movement with the second set of rails and at least one first hydraulic cylinder mounted to the first mounting plate and coupled with the first die. The at least one first hydraulic cylinder is adapted to expand and contract causing during expansion the first and second dies to move interdependently, via the first mounting plate and the first and second rails into the closing position.

In another embodiment, the sub-assembly is a closed loop sub-assembly further comprising a second mounting plate connected for movement with the first set of rails spaced along the first and second rails from the first mounting plate. The sub-assembly further comprises at least one second hydraulic cylinder mounted to the second mounting plate and coupled with the second die. The at least one second hydraulic cylinder is adapted to expand and contract in unison with the expansion and contraction of the at least one first hydraulic cylinder whereby expansion of the at least one second hydraulic cylinder causes the first and second dies to move interdependently, via the second mounting plate and the first and second rails into the closing position. It is envisaged that the second hydraulic cylinder is connected either directly to the second die or indirectly to the second die in the event the second die comprises a second slave die.

In another embodiment the first and second rails each have an elongate groove extending along its length and the support table has fixedly mounted thereto guide members each having edge surface portions slidingly extending into and along the elongate groove of each of the first and second rails.

In yet another embodiment, the pre-crush die further comprises at least one drive coupler mechanically coupling the first and second rails whereby the first and second dies are further maintained equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed during interdependent movement of the first and second dies and first and second rails. The drive coupler in effect improves the tolerance of accuracy in the interdependent movement of the first and second dies.

In another embodiment the at least one drive coupler comprises a first toothed rack mounted to the first rail, a second toothed rack mounted to the second rail, and a toothed pinion mounted to the support table for rotation therewith. The toothed pinion is mounted in meshing relation with the first and second toothed racks.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the present invention reference may be had by way of example to the accompanying diagrammatic drawings.

FIGS. 1A and 1B are schematic drawings of the present invention;

FIG. 2 is a perspective view of an embodiment of the present invention;

FIG. 3 is a partial perspective view of the sub-assembly of the embodiment of FIG. 2; and,

FIG. 4 is another partial perspective view of the sub-assembly of the embodiment of FIG. 2.

DETAILED DESCRIPTION

The present invention relates to a pre-crush die assembly for controlled deformation of a tubular member, such as, for example, a pipe or conduit having a circular or non-circular cross-section, to be used in a subsequent hydroforming operation.

Referring to FIGS. 1A and 1B there is shown a schematic view of the pre-crush die sub-assembly 10. The sub-assembly 10 comprises a first die 12 and a second die 14. The dies 12 and 14 are carried by carriages 16 and 18 respectively. Each of the dies 12 and 14 has a corresponding hydraulic cylinder 20 and 22 coupled to it. The hydraulic cylinders 20 and 22 each have a cylinder portion 24 and a piston portion 26 and are run by a hydraulic power pack (not shown). The piston portion 26 is coupled to the corresponding die 12, 14. The cylinders 24 of each of the hydraulic cylinder is 20, 22 is connected to a corresponding carriage 16, 18. In this manner, a closed loop sub-assembly 10 is provided. In the open position shown in FIG. 1B, a tubular member 30 is shown located between the die faces 11, 13 of dies 12 and 14. The tubular member 30 has a centerline 32 that is positioned equidistant from each of the die faces 11, 13 of dies 12 and 14. During the expansion of the hydraulic cylinders 20 and 22, the dies 12 and 14 are moved into a closed or closing position whereby the die faces 11, 13 of the dies 12, 14 engage and deform corresponding surface portions 15, 17 of the tubular member 30. The expansion of the hydraulic cylinders 20, 22 also acts on the carriages 16 and 18 to push the carriages apart resulting in the die faces 11, 13 of the dies 12 and 14 moving towards each other in opposing directions to continuously maintain the first and second dies 12, 14 equidistant from the centerline 32 of the tubular member 30.

In FIGS. 1A and 1B, the pre-crush die sub-assembly 10 has been shown to be free floating. It should be understood that this sub-assembly would normally be mounted to a support table (not shown) for sliding movement with the support table. In this respect, the support table would include trackways along which the carriages 16 and 18 would travel in a guided manner.

Referring to FIGS. 2 through 4, there is shown a pre-crush die assembly 40 for controlled deformation of a first tubular member 42 and a second tubular member 44. The tubular members 42 and 44 each have a respective centerline 46 and 48 shown in dotted line extending through the tubular member. The tubular members 42 and 46 are shown to comprise bent pipe of similar configuration. The end portions 50 of the tubular members 42 and 44 are shown mounted within fastening devices or releasable clamp devices 52. The clamp devices 52 are provided with a receiving cradle 54 into which the tubular members 42 and 44 are received. The clamp device 52 has an arm member 56 that is adapted to move into a clamping position with the tube end portions 50. The clamping devices 52 are positioned on support table 58 so as to support the first and second tubular members 42 and 44 relative with and to the support table 58. As shown in FIG. 1, the first and second tubular members 42 and 44 are supported relative with the support table 58 above a top plate 64.

The support table 58 comprises a base frame structure 60 that includes legs 62. Mounted to the top of the base frame structure 60 is a top plate 64. The top plate 64 has a series of wear plates 66 mounted thereon. In particular, the wear plates 66 extend from the end portions 72 of the top plate 64 and terminate before the middle of the top plate 64. Each of the wear plates is held in place by guide members or guide brackets 68 which are secured by means of bolts 70 that pass through the guide brackets 68 and wear plates 66 and through the top plate 64 of the support table 58. Each of the guide brackets 68 has a protruding track edge portion 74, the purpose of which will be described hereinafter.

A closed loop sub-assembly 80 is mounted relative to the top plate 64 of the support table 58 for movement relative to the support table 58.

The sub-assembly includes a first set of two rails 82 and a second set of three rails 84 inter-spaced from the first set of rails 82. Each of the rails 82 and 84 is adapted to rest and slide on two wear plates 66 whereby the length of the rails 82 and 84 extend across and move along the length of the support table top plate 64. Each of the rails 82 and 84 is adapted to slide relative to two rail plates 66. Each of the rails 82 and 84 has an elongate groove 86 that extends along the length of the rail. The track edge portion 74 extends into the recessed groove to limit the sliding motion of the rails 82 and 84 in opposing directions along the length of the support table 58.

The second set of rails 84 are interconnected by a first mounting plate 88. The first mounting plate 88 is provided with a series of bolts 90 that extend through the first mounting plate 88 and are secured within threaded apertures in the second set of rails 84. Accordingly, the first mounting plate 88 acts to group the second set of rails 84 for uniform motion.

A second mounting plate 100 is mounted to the first set of rails 82 by means of bolts 102 that pass through the surface of the second mounting plate 100 and the threaded apertures located in the first set of rails 82. In effect, the second mounting plate 100 acts to group the first set of rails 82 and for uniform motion.

The sub-assembly 80 further includes two spaced apart servomotors 104 that are mounted to the first mounting plate 88. Servomotors 104 have a cylinder portion 106 and a piston portion 108. The hydraulic cylinders 104 are in effect hydraulically driven piston cylinders. The cylinder 106 of the hydraulic cylinders 104 are each connected by a frame bracket 110 which is secured by bolts 112 to the first mounting plate 88.

Similarly, a pair of second hydraulic cylinders 114 are mounted to the second mounting plate 100. The second hydraulic cylinders 114 comprise a cylinder portion 116 and a piston portion 118. The second hydraulic cylinders 114 are surrounded by a frame bracket 120 and connected to the second mounting plate 100 by bolts 122.

The closed loop sub-assembly 80 further comprises a first master die 124 and a first slave die 126 mounted to the first set of rails 82 between the first and second mounting plates 88, 100. The first master die 124 and the first slave die 126 are mounted by suitable means, such as, for example bolts 123 passing through the first set of rails 82 and into the dies 124, 126 or alternatively the dies 124, 126 have protruding key members that are inserted into receiving slots in the rails (124, 126).

The closed loop sub-assembly 80 further comprises a second master die 128 and a second slave die 130 mounted to the second set of rails 84 between the first and second mounting plates 88, 100.

By mounting of the first master die 124 and the first slave die 126 to the first set of rails 82, the first master die 124 and the first slave die 126 are adapted to move in unison relative to each other with the first set of rails 82. By mounting the second master die 128 and the second slave die 130 to the second set of rails 84, the second master die 128 and the second slave die 130 are adapted to move in unison with each other and with movement of the second set of rails 84.

The pistons 108 of the first hydraulic cylinders 104 are connected via a bracket 132 to the first master die 124. Similarly, the piston 118 of the second hydraulic cylinders 114 are each connected through a bracket 134 with the second master die 128.

As shown in FIG. 2, the first master die 124 has a punch surface 136 opposite to a punch surface 138 of the second slave die 130. Similarly, the first slave die 126 has a punch surface 140 that is opposed to or across from the punch surface 142 of the second master die 130. Punch surfaces 136 and 138 may be said to be complimentary to each other as they will in effect have opposing contours. For example where the contour of one die punch surface is concave the other would be convex. Similarly, each of the punch surfaces 140 and 142 of the first slave die 126 and second master die 128 are complimentary.

During operation, the first and second tubular members 42 and 44 are secured by the clamping devices 52 with the closed loop sub-assembly 80 in its open position. This is shown substantially in FIG. 2. In the open position, the first master die 126 and the second slave die 130 are positioned on opposing sides of the first tubular member 42. The first master die 124 and the second slave die 130 are spaced in non-contacting relation to the first tubular member 42 equidistant from the centerline 46 of the first tubular member 42 adjacent the portion of the first tubular member 42 to be deformed. By the portion it is meant that the first master die 124 and the second slave die 130 may not deform the entire length of the tubular member 42 but only selected portions of this member 42. As a consequence it is only necessary that the punch surfaces of the first master die 124 and the second slave die 130 that come into contact with the portions of the first tubular member 42 be maintained equidistant from the centerline 46 of the first tubular member 42 adjacent that portion to be deformed.

The second master die 128 and the first slave die 126 in the open position shown in FIG. 2 are positioned on opposing sides of the second tubular member 44 in non-contacting relation therewith. The second master die 128 and the first slave die 126 are positioned equidistant from the centerline 48 of the second tubular member 44 adjacent the portion of the second tubular member 44 to be deformed.

Once the clamping device 52 indicates that all end portions 50 of the first and second tubular members 42, 44 are clamped in place, such as for example by the use of limit switches 200, then the closed loop sub-assembly is operated to pre-crush the tubular members 42 and 44. This is accomplished by actuating the first and second hydraulic cylinders 104 and 114 at the same time to expand causing the pistons 108 and 118 to push against the first master die 124 and the second master die 128. At the same time the first mounting plate 88 may be displaced in a direction opposite to the expansion of the first piston 108. Similarly, the second mounting plate 100 may be displaced in a direction opposite to the expansion of the piston 118. This is due to the closed loop effect of the first and second mounting plates 88 and 100 being mounted to the second and first set of rails 84, 82, respectively. Consequently the first master die 124 and the second slave die 130 move interdependently of each other via the first and second mounting plates 88, 100 and the first and second rails 82, 84 in opposing directions towards each other into a closing position engaging and deforming the first tubular member 42. During this interdependent movement the first master die 124 and the second slave die 130 remain equidistant from the centerline 46 of the first tubular member 42 adjacent the portion of the first tubular member 42 to be deformed. Similarly, the second master die 128 and the first slave die 126 move interdependently of each other, via the first and second mounting plates 88, 100 and the first and second sets of rails 82, 84, in opposing directions towards each other into the closing position to deform the second tubular member 44. The second master die 128 and the first slave die 126 remain equidistant from the centerline 48 of the second tubular member 44 adjacent the portion of the second tubular member 44 being deformed as the second master die 128 and the first slave die 126 move from the open position to the closing position.

Additional limit switches (not shown) are utilized in order to determine when the dies have reached their closing positions. Thereafter, the hydraulic cylinders 104 and 114 may be contracted to move the dies from a closed position back into an open position which is again monitored by limit switches (not shown). At this time, the clamping devices 52 may be released to allow the removal of the pre-crushed tubular members 42 and 44 from the die assembly 40.

To further limit the closing of the dies, the table top plate 64 has an end bracket 146 to which stops 148 are attached. The stops 148 at each end of the support table 58 are adapted to engage one of the sets of rails 82, 84 that move towards the corresponding stops 148 to thereby limit movement of the rails 82, 84 during the closing operation. The stops 82, 84 provide a positive mechanical stop movement for the rails 82, 84. Mounted to the top of each of the brackets 146 are protection guards 150.

It should be understood that the embodiment described deals with a first master die and a second slave die. It is envisaged that more than one slave dies could be utilized so that more than two tubular members could be deformed at the same time. Alternatively, only master dies directly coupled to the hydraulic cylinders may be utilized so that only a single tubular member is pre-crushed.

While the present invention provides for a uniform crushing of a tubular member about the tubular members centerline, to improve the tolerance of this symmetrical crushing about the centerline of the tubular member, the embodiment further employs as shown in FIG. 4 a pair of drive couplers 152 which mechanically couple one rail of each of the first and second sets of rails 82, 84 so that the first master die 124 and first slave die 126 and the second master die 128 and second slave die 130 are further maintained equidistant from the centerlines 46, 48 of the tubular members 42, 44 during deformation. Each of the drive couplers 152 comprises a first tooth rack 160 mounted to one of the first set of rails 82 and a second tooth rack 162 mounted to one of the second set of rails 84. The drive coupler 156 further includes a tooth pinion 166 mounted for rotation at axis 167 with the support table 58 via plate 168. The teeth of the pinion 166 is located in meshing relation with the teeth of the first and second toothed racks 168. As a consequence, opposing motion of the first set of rails 82 relative to the second set of rails 84 is governed by this drive coupler 156 to improve the tolerance of the relative movement of the dies.

While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the claims. 

1. A pre-crush die assembly for controlled deforming of at least a portion of a tubular member to be used in a subsequent hydroforming operation, the tubular member having a centerline extending therethrough and the pre-crush die assembly comprising: a support table for supporting the tubular member relative therewith; and, a sub-assembly mounted to the support table for movement relative thereto, the sub-assembly comprising a first die and a second die both adapted to move relative to the support table and interdependently of each other between an open position and a closing position engaging and deforming the portion of the tubular member, in the open position, the first and second dies being positioned in spaced non-contacting relation to opposing sides of the tubular member, and the first and second dies moving interdependently in opposing directions towards each other into the closing position to continuously maintain the first and second dies equidistant from the centerline of the tubular member adjacent the portion of the tubular member being deformed.
 2. The pre-crush die assembly of claim 1 wherein in the open position the first and second dies are spaced equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed.
 3. The pre-crush die assembly of claim 2 further comprising at least one drive coupler mechanically coupling the first and second dies to further maintain the first and second dies equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed during interdependent movement of the first and second dies from the open position to the closing position.
 4. The pre-crush die assembly of claim 2 wherein the sub-assembly further comprises a first carriage for supporting the first die and a second carriage for supporting the second die, the support table comprising a guide trackway along which the first and second carriages move.
 5. The pre-crush die assembly of claim 4 further comprising at least one drive coupler mechanically coupling the first and second carriages whereby the first and second dies are further maintained equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed during interdependent movement of the first and second dies.
 6. The pre-crush die assembly of claim 4 wherein the first and second carriages each comprises at least one elongate rail having an elongate groove extending along its length and the guide trackway comprises a guide member mounted to the support table having an edge surface portion extending into and along the elongate groove of the elongate rail.
 7. The pre-crush die assembly of claim 6 further comprising at least one drive coupler mechanically coupling the elongate rails of the first and second carriages whereby the first and second dies are further maintained equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed during interdependent movement of the first and second dies.
 8. The pre-crush die assembly of claim 5 wherein the at least one drive coupler comprises a first toothed rack mounted to the first carriage of the first die, a second toothed rack mounted to the second carriage of the second die, and a toothed pinion mounted to the support table for rotation therewith and the toothed pinion being mounted in meshing relation with the first and second toothed racks.
 9. The pre-crush die assembly of claim 7 wherein the at least one drive coupler comprises a first toothed rack mounted to the elongate rail of the first carriage, a second toothed rack mounted to the elongate rail of the second carriage, and a toothed pinion mounted to the support table for rotation therewith and the toothed pinion being mounted in meshing relation with the first and second toothed racks.
 10. The pre-crush die assembly of claim 4 further including stops mounted to the support table for engaging the first and second carriages to limit movement of the first and second carriages into the closing position.
 11. The pre-crush die assembly of claim 8 further including stops mounted to the support table for engaging the elongate rails of the first and second carriages to limit movement of the first and second dies into the closing position.
 12. The pre-crush die assembly of claim 2 further comprising a plurality of fastening devices carried by the support table for removably securing the tubular member between the first and second dies when in the open position.
 13. The pre-crush die assembly of claim 2 wherein the sub-assembly comprises: a first set of rails adapted to slide relative to the support table; a second set of rails interspaced with the first set of rails adapted to slide relative to the support table in directions opposite to those of the first rails; the first die mounted to the first set of rails; and, the second die mounted to the second set of rails.
 14. The pre-crush die of claim 13 wherein the sub-assembly further comprises: a first mounting plate connected for movement with the second set of rails; at least one first hydraulic cylinder mounted to the first mounting plate and coupled with the first die, and the at least one first hydraulic cylinder adapted to expand and contract causing during expansion the first and second dies to move interdependently, via the first mounting plate and the first and second rails into the closing position.
 15. The pre-crush die of claim 14 wherein the sub-assembly comprises a closed loop sub-assembly further comprising: a second mounting plate connected for movement with the first set of rails spaced along the first and second rails from the first mounting plate; and at least one second hydraulic cylinder mounted to the second mounting plate and coupled with the second die, and the at least one second hydraulic cylinder adapted to expand and contract in unison with the expansion and contraction of the at least one first hydraulic cylinder whereby expansion of the at least one second hydraulic cylinder causing the first and second dies to move interdependently, via the second mounting plate and the first and second rails into the closing position.
 16. The pre-crush die of claim 15 wherein the at least one second hydraulic cylinder is indirectly coupled with the second die.
 17. The pre-crush die assembly of claim 15 wherein the first and second rails each have an elongate groove extending along its length and the support table has fixedly mounted thereto guide members having edge surface portions slidingly extending into and along the elongate groove of each of the first and second rails.
 18. The pre-crush die assembly of claim 16 wherein the first and second rails each have an elongate groove extending along its length and the support table has fixedly mounted thereto guide members having edge surface portions slidingly extending into and along the elongate groove of each of the first and second rails.
 19. The pre-crush die assembly of claim 13 further comprising at least one drive coupler mechanically coupling the first and second rails whereby the first and second dies are further maintained equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed during interdependent movement of the first and second dies and first and second rails.
 20. The pre-crush die assembly of claim 19 wherein the at least one drive coupler comprises a first toothed rack mounted to the first rail, a second toothed rack mounted to the second rail, and a toothed pinion mounted to the support table for rotation therewith and the toothed pinion being mounted in meshing relation with the first and second toothed racks.
 21. The pre-crush die assembly of claim 19 further including stops mounted to the support table for engaging the first and second rails to limit movement of the first and second carriages into the closing position.
 22. The pre-crush die assembly of claim 15 further comprising a plurality of fastening devices carried by the support table for removably securing the tubular member between the first and second dies when in the open position.
 23. The pre-crush die assembly of claim 15 further comprising at least one drive coupler mechanically coupling the first and second rails whereby the first and second dies are further maintained equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed during interdependent movement of the first and second dies and first and second rails.
 24. The pre-crush die assembly of claim 23 wherein the at least one drive coupler comprises a first toothed rack mounted to the first rail, a second toothed rack mounted to the second rail, and a toothed pinion mounted to the support table for rotation therewith and the toothed pinion being mounted in meshing relation with the first and second toothed racks.
 25. The pre-crush die assembly of claim 16 further comprising a plurality of fastening devices carried by the support table for removably securing the tubular member between the first and second dies when in the open position.
 26. The pre-crush die assembly of claim 16 further comprising at least one drive coupler mechanically coupling the first and second rails whereby the first and second dies are further maintained equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed during interdependent movement of the first and second dies and first and second rails.
 27. The pre-crush die assembly of claim 26 wherein the at least one drive coupler comprises a first toothed rack mounted to the first rail, a second toothed rack mounted to the second rail, and a toothed pinion mounted to the support table for rotation therewith and the toothed pinion being mounted in meshing relation with the first and second toothed racks.
 28. A pre-crush die assembly for controlled deforming of at least a portion of a tubular member to be used in a subsequent hydroforming operation, the tubular member having a centerline extending therethrough and the pre-crush die assembly comprising: a support table for supporting the tubular member relative therewith; and, a closed loop sub-assembly mounted to the support table for movement relative thereto, the closed loop sub-assembly comprising: a first set of rails adapted to slide relative to the support table; a second set of rails interspaced with the first set of rails adapted to slide relative to the support table in directions opposite to those of the first rails; a first mounting plate connected for movement with the second set of rails; a second mounting plate connected for movement with the first set of rails spaced along the first and second rails from the first mounting plate; at least one first hydraulic cylinder mounted to the first mounting plate; at least one second hydraulic cylinder mounted to the second mounting plate; at least one first die mounted to the first set of rails between the first and second mounting plates and coupled with the first hydraulic cylinder; at least one second die mounted to the second set of rails between the first and second mounting plates and coupled with the second hydraulic cylinder, the at least one first die and the at least one second die being positioned on opposing sides of the tubular member in an open position spaced in non-contacting relation to the tubular member equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed; and the first and second hydraulic cylinders adapted to expand and contract, and causing, during expansion, the first and second dies to move interdependently, via the first and second mounting plates and the first and second rails, in opposing directions towards each other into a closing position engaging and deforming the tubular member whereby the first and second dies remain equidistant from the centerline of the tubular member adjacent the portion of the tubular member being deformed as the first and second dies move from the open position to the closing position.
 29. The pre-crush die of claim 28 wherein the at least one first and second hydraulic cylinders each comprise a hydraulic cylinder and piston with the piston being coupled directly to a corresponding one of the first and second dies.
 30. A pre-crush die assembly for controlled deforming of at least a portion of each of first and second tubular members to be used in a subsequent hydroforming operation, the first and second tubular members each having a centerline extending therethrough and the pre-crush die assembly comprising: a support table for supporting the first and second tubular members relative therewith; and, a closed loop sub-assembly mounted to the support table for movement relative thereto, the closed loop sub-assembly comprising: a first set of rails adapted to slide relative to the support table; a second set of rails interspaced with the first set of rails adapted to slide relative to the support table in directions opposite to those of the first rails; a first mounting plate connected for movement with the second set of rails; a second mounting plate connected for movement with the first set of rails spaced along the first and second rails from the first mounting plate; at least one first hydraulic cylinder mounted to the first mounting plate; at least one second hydraulic cylinder mounted to the second mounting plate; a first master die and a first slave die mounted to the first set of rails between the first and second mounting plates and the first master die being directly coupled with the first hydraulic cylinder; a second master die and a second slave die mounted to the second set of rails between the first and second mounting plates and the second master die being directly coupled with the second hydraulic cylinder, the first master die and the second slave die being positioned on opposing sides of the first tubular member in an open position spaced in non-contacting relation to the first tubular member equidistant from the centerline of the first tubular member adjacent the portion of the first tubular member to be deformed; the second master die and the first slave die being positioned on opposing sides of the second tubular member in the open position spaced in non-contacting relation to the second tubular member equidistant from the centerline of the second tubular member adjacent the portion of the second tubular member to be deformed; the first and second hydraulic cylinders adapted to expand and contract, and causing, during expansion: the first master die and the second slave die to move interdependently, via the first and second mounting plates and the first and second sets of rails, in opposing directions towards each other into a closing position engaging and deforming the first tubular member whereby the first master die and second slave die remain equidistant from the centerline of the first tubular member adjacent the portion of the first tubular member being deformed as the first master die and second slave die move from the open position to the closing position, and the second master die and the first slave die to move interdependently, via the first and second mounting plates and the first and second sets of rails, in opposing directions towards each other into the closing position engaging and deforming the second tubular member whereby the second master die and first slave die remain equidistant from the centerline of the second tubular member adjacent the portion of the second tubular member being deformed as the second master die and first slave die move from the open position to the closing position.
 31. The pre-crush die of claim 30 wherein the at least one first and second hydraulic cylinders each comprise a hydraulic cylinder and piston with the piston being coupled directly to a corresponding one of the first and second master dies.
 32. The pre-crush die assembly of claim 30 wherein the first and second rails each have an elongate groove extending along its length and the support table has fixedly mounted thereto guide members having edge surface portions slidingly extending into and along the elongate groove of each of the first and second rails.
 33. The pre-crush die assembly of claim 30 further comprising at least one drive coupler mechanically coupling the first and second rails whereby the first and second dies are further maintained equidistant from the centerline of the tubular member adjacent the portion of the tubular member to be deformed during interdependent movement of the first and second dies and first and second rails.
 34. The pre-crush die assembly of claim 33 wherein the at least one drive coupler comprises a first toothed rack mounted to the first rail, a second toothed rack mounted to the second rail, and a toothed pinion mounted to the support table for rotation therewith and the toothed pinion being mounted in meshing relation with the first and second toothed racks.
 35. The pre-crush die assembly of claim 30 further including stops mounted to the support table for engaging the first and second rails to limit movement of the first and second carriages into the closing position.
 36. A method of controlled deformation of at least a portion of a tubular member to be used in a subsequent hydroforming operation by first and second dies, the method comprising the steps of: positioning the tubular member between the first and second dies in spaced non-contacting relation therewith; and, interdependently moving the first and second dies towards each other to engage and deform the tubular member while continuously maintaining the first and second dies equidistant from the centerline of the tubular member adjacent the portion of the tubular member being deformed.
 37. The method of claim 36 wherein during the step of positioning the tubular member between the first and second dies the centerline of the tubular member adjacent the portion to be deformed is spaced equidistant from the first and second dies. 